The present invention relates to a pharmacological delivery implement. More particularly, the present invention relates to a pharmacological delivery implement for use with repair devices implantable within the cardiac system.
Cardiac repair devices, such as prosthetic valves, annuloplasty prosthesis, vascular grafts, etc., have conventionally been implanted into the heart or surrounding vessels to repair or strengthen diseased or ailing members of the cardiac system. However, many of the cardiac repair devices include prosthetic materials that are not native to the internal system of patients. As such, a patient often has an adverse reaction to the implantation of non-native materials causing chronic inflammation and excessive scar tissue, i.e. pannus.
Various types of prosthetic heart valves, used to replace diseased natural human heart valves, are known in the art. The actual shape and configuration of any particular prosthetic heart valve is, of course, dependent to some extent upon the valve being replaced (i.e. mitral valve, tricuspid valve, aortic valve, and pulmonary valve). In general terms, however, the prosthetic heart valve design attempts to replicate the function of the heart valve being replaced and thus will include valve leaflet-like structures. With this in mind, prosthetic heart valves including valve leaflets are generally categorized as either forming relatively flexible leaflets or relatively rigid leaflets.
The category including prosthetic heart valves formed with relatively flexible leaflets includes bioprosthetic heart valves having a substantially annular, fabric-covered stent supporting a number of leaflets made of a biological (e.g. porcine, pericardial tissue, etc.) or synthetic (e.g. polymeric) material. Prosthetic heart valves categorized as forming relatively rigid leaflets include mechanical prosthetic heart valves. A typical mechanical heart valve includes an annular valve housing or body to provide a passageway for blood flow. Relatively rigid leaflets are rotatably mounted to the annular housing and rotate to open or close the blood flow passageway.
Both flexible and rigid leaflet prosthetic heart valves typically include an annularly-extending, flexible sewing ring attached to the fabric-covered stent or valve housing, respectively. Upon implantation of the prosthetic heart valve, the sewing ring is attached to the heart valve annulus surrounding the heart valve to be repaired, thereby, attaching the entirety of the prosthetic heart valve to the heart valve annulus.
During use of a prosthetic heart valve, inflammation can occur and fibrotic scar tissue may form. The fibrotic scar tissue can extend from the sewing ring to the valve leaflets, thereby, causing stenosis and/or regurgitation. Upon occurrence of any such problems, a prosthetic heart valve is typically removed and replaced with a new prosthetic heart valve. In particular, flexible leaflet prosthetic heart valves experiencing inflammation, stenosis, and/or regurgitation must be removed in the relatively near future to prevent further harm to the heart valve and surrounding material.
Due to the mechanical attributes of the mechanical valve, a mechanical valve causing inflammation, stenosis, and/or regurgitation must be removed almost immediately following detection of a problem in order to prevent dire consequences to the patient. Even if prosthetic valve removal can be performed before such dire consequences occur, the removal and replacement procedure once again exposes the patient to the general dangers of surgery along with additional periods of heart stoppage. Due to the complicated nature of the heart vessel, it is difficult to deliver pharmacological agents targeted to the heart valve annulus tissue to decrease inflammation, stenosis, regurgitation, etc.
Annuloplasty prosthesis, generally categorized as either annuloplasty rings or annuloplasty bands, are employed in conjunction with valvular reconstructive surgery to assist in the correction of heart valve defects such as stenosis and valvular insufficiency. The purpose of the annuloplasty prosthesis is to restrict and/or support the heart valve annulus to correct and/or decrease valvular insufficiency. A posterior portion of the annulus is often diseased or dilated and not well supported by heart tissue. An anterior portion of the annulus, in contrast, is well supported by surrounding heart tissue.
In general terms, annuloplasty rings completely encompass both the anterior and posterior portions of the valve annulus. Annuloplasty bands, on the other hand, are specifically designed to primarily encompass only a portion of the valve annulus. For example, an annuloplasty band may be configured to encompass only the posterior portion of the valve annulus, thus promoting natural movement of the anterior portion of the heart valve annulus.
Inflammation and excessive scar tissue also typically form on annuloplasty prostheses causing similar problems as described above with respect to prosthetic heart valves. Also similar as described above, annuloplasty prosthesis causing excessive inflammation or scar tissue typically must be explanted and replaced, thereby, introducing the patient to the dangers presented by additional surgeries including anesthesia, infection, extended periods of heart stoppage, etc. Similar problems, as those discussed above with respect to prosthetic heart valves and annuloplasty prostheses, can be caused with other cardiac repair devices such as vascular grafts, etc.
As described above, implantation of prosthetic heart valves, annuloplasty bands, and other cardiac repair devices may lead to excessive inflammation, scar tissue, stenosis, and/or regurgitation. As such, a need exists for a cardiac repair device that prevents or decreases the occurrence of inflammation, excessive scar tissue, stenosis, and/or regurgitation, thereby, decreasing the need for explantation of the cardiac repair devices that, in turn, decreases the dangers to which a particular patient is exposed.